Bond bubble finally bursting? Rates creep up

U.S. stocks ended down for a fourth straight day Monday. But bonds were the real story, as yields continued to creep higher amid chatter that the Federal Reserve could begin winding down its stimulus sooner rather than later.

Worries that the central bank could taper its $85 billion a month in bond purchases, or quantitative easing, as early as September has spurred a huge sell-off in bonds.

Investors have yanked nearly $20 billion from bond mutual funds and exchange traded funds so far in August. That's the fourth highest pullback ever, according to TrimTabs data. In June, investors took out $69.1 billion -- the highest on record.

"As much as bond professionals say they've never really liked QE, they're trading as though they miss it already," said Jim Vogel, interest rate strategist at FTN Financial.

The Fed will remain in focus this week as investors look ahead to Wednesday. That's when the Fed releases minutes from its last monetary policy meeting. The Kansas City Fed also hosts its annual conference in Jackson Hole, Wyo. later this week.

What's moving: Shares of Chesapeake Energy(CHK) initially rose following news that Carl Icahn boosted his stake in the natural gas company to almost 10%. But the stock headed lower by the end of the day.

Apple? Chesapeake a bigger hit for Icahn

Apple,(AAPL) which Icahn announced a "large" position in last week, continued to climb, hitting the highest level in seven months. And the stock was the hottest topic among traders on StockTwits.

FUNERALMAN21:$AAPL shorts and profit takers get your hats, get your coats, and go home I'm 100% sure this stock will be bigger then anyone has predicted.

daytradingshrink:$AAPL todays theme song has gotta be stairway to heaven. really thought it would break this intraday uptrend and move sideways. strong!

The earnings calendar was light Monday, but results are due from J.C. Penney(JCP), Best Buy(BBY) and Home Depot(HD) on Tuesday. Targe(TGT)t and Hewlett-Packar(HPQ)d are also set to report later in the week.